首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4300712篇
  免费   335345篇
  国内免费   14218篇
耳鼻咽喉   59364篇
儿科学   136845篇
妇产科学   111954篇
基础医学   661673篇
口腔科学   115411篇
临床医学   390377篇
内科学   776781篇
皮肤病学   107582篇
神经病学   358239篇
特种医学   166548篇
外国民族医学   509篇
外科学   658441篇
综合类   120321篇
现状与发展   24篇
一般理论   2667篇
预防医学   359432篇
眼科学   100692篇
药学   300859篇
  26篇
中国医学   11472篇
肿瘤学   211058篇
  2021年   56595篇
  2020年   36122篇
  2019年   59253篇
  2018年   74871篇
  2017年   57262篇
  2016年   63534篇
  2015年   76493篇
  2014年   111219篇
  2013年   176952篇
  2012年   127296篇
  2011年   133649篇
  2010年   127902篇
  2009年   128918篇
  2008年   119611篇
  2007年   127603篇
  2006年   135883篇
  2005年   131141篇
  2004年   130977篇
  2003年   121232篇
  2002年   110162篇
  2001年   150262篇
  2000年   144981篇
  1999年   134834篇
  1998年   70756篇
  1997年   66739篇
  1996年   64824篇
  1995年   60086篇
  1994年   54116篇
  1993年   50364篇
  1992年   96340篇
  1991年   92931篇
  1990年   89255篇
  1989年   87025篇
  1988年   80215篇
  1987年   78731篇
  1986年   74020篇
  1985年   73154篇
  1984年   61846篇
  1983年   55589篇
  1982年   46200篇
  1981年   43311篇
  1980年   40649篇
  1979年   53219篇
  1978年   44141篇
  1977年   39001篇
  1976年   36388篇
  1975年   36396篇
  1974年   39505篇
  1973年   37703篇
  1972年   35319篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
14.
Vestibular function laboratories utilize a multitude of diagnostic instruments to evaluate a dizzy patient. Caloric irrigators, oculomotor stimuli, and rotational chairs produce a stimulus whose accuracy is required for the patient response to be accurate. Careful attention to everything from cleanliness of equipment to threshold adjustments determine on a daily basis if patient data are going to be correct and useful. Instrumentation specifications that change with time such as speed and temperature must periodically be checked using calibrated instruments.  相似文献   
15.
16.
17.
18.

Background

Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.

Methods

PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD. Clinical outcomes of intra- and postoperative times, reoperation for bleeding and surgical site infection were evaluated.

Results

Five observational studies comparing 340 MIS vs 414 MS patients were eligible for qualitative and quantitative review. The quality of evidence assessed using the Newcastle-Ottawa scale was good for all included studies. Meta-analysis demonstrated increased cardiopulmonary bypass time for MIS patients (weighted mean difference [WMD], 0.487; 95% confidence interval [CI], 0.365-0.608; P < .0001). Similarly, aortic cross-clamp time was longer in patients undergoing MIS (WMD, 0.632; 95% CI, 0.509-0.755; P < .0001). No differences were found in operative mortality, reoperation for bleeding, surgical site infection, or hospital stay.

Conclusions

MIS for MVD have similar short-term outcomes compared to MS. This adds value to the use of minimally invasive methods for multivalvular surgery, despite conferring longer operative times. However, the paucity in literature and learning curve associated with MIS warrants further evidence, ideally randomized control trials, to support these findings.
  相似文献   
19.
20.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号